Process for the preparation of hydrazino pyridine compounds



Patented May 29, 1928.

PATENT OFFICE.

UNITED STATES cum 31TH, or BERLIN, GERMANY.

PROCESS FOR THE PREPARATION OF HYDRAZINO PYRIDINE COMPOUNDS.

No Drawing. Application filed June 16, 1926, Serial No. 116,437, and in Germany November 11, 1924.

The object of this invention is the preparation of beta-pyridyl-hydrazine and its derivatives. I have discovered that these compounds can be prepared by the action of stannous chloride or similar reducing agent on beta-pyridyl-diazonium chloride or its corresponding derivative.

Example 1.

cc. water. The diazo solution is then poured into an ice cooled solution of 300 grams stannous chloride in 250 grams water. The tin double salt of the hydrazine precipitates and after standing a. short time is filtered. The free base is isolated by decomposing the double salt with alkali, repeated extraction of the alkaline solution with ether and subsequent evaporation of the latter. The free base forms white crystals, melting at-5355. The compound becomes brown in the air, can not be distilled undecomposed, and reduces Fehlings solution immediately in the cold. The reaction is shown by the following:

NSN- C1 NH-NHzHCl Example 2.

Alpha-chlor-betM-hydmzino-pyfldWE-Gi grams of .alphachlor-beta -ami'no pyridine are dissolved in about 500 cc. concentrated short time, the -reaction .mixture is added,

with stirring, to a well cooled solution of 300 ams stannous chloride in 250 cc. concentrated hydrochloric acid. A faintly pink colored tin double salt of alpha-chlor-beta hydrazino-pyridine precipitates on standing. By decomposing the double salt with alkali andrepeated extraction of the alkaline solution with ether and subsequent evaporation of the latter, the hydrazine is obtained as faintly yellowish needles. .Yield-about On recrystallization from benzol the hydrazine is obtained as colorless needles and melts at 129130. The compound reduces Fehlings solution on warming slightly. The course of the reaction is similar to that of Example 1.

The compounds are used therapeutically,

oras initial materials in "the preparation of 7 products which'are of importance therapeutically What I claim is 1. Process for the preparation of a ,B-hying drazino pyridine compound which comprises diazotizing the corresponding B-amino pyr1- dine and reducing the diazonium compound thus formed.

2. Process for the preparation of a B-hydrazino pyridine compound which comprises diazotizing-the corresponding ,B-amino pyridine and reducing the diazonium 'cornpoun thus formed by means of stannous chloride.

3. Process for the preparation of a substituted B-hydrazino pyridine compound which comprises diazotizing the corresponding substituted ,B-amino pyridine and reducthe .substituted diazonium compound thus formed.

4. Process for the preparation of a ,B-hydrazino pyridine compound which comprises reducing the corresponding ,B-pyridine diazonium chloride. 1

'5. Process for the preparation of a ,B-hy: drazino pyridine compound which comprises reducing the corresponding ,B-pyridine di-' dine and reducing the diazonium compound thus formed by means of stannous chloride by treatment of the solutlon with alkali and .and recoveringthe' free hydrazine compound subsequent-extraction of the solution with ether. 7. Process for the preparation of a ,8-hydrazino pyridine compound which comprises 5 reducing'the corresponding B-pyridine diazonium chloride, and recovering the free hydrazine compound by treatment of the solution with alkali and subsequent extraction of the solution with ether.

Signed at Berlin, in the province of Bran- 1 denburg and State of Prussia, this 1st day of May, A. D. 1926.

DR. CURT BATH. 

